Emotional Dot-Probe Task – PsyFlow Version

This task implements an emotional dot-probe paradigm to measure attentional bias towards emotional versus neutral stimuli. Participants respond to the location of a target dot that appears after the brief presentation of two face stimuli. The task is built using the PsyFlow framework.

Task Overview

Participants first view a fixation cross, followed by a brief presentation of a pair of face images (e.g., positive vs. neutral, negative vs. neutral). After a short interval, a small target dot appears on either the left or right side. Participants must quickly indicate the location of the dot by pressing the left or right arrow key.

This task assesses attentional biases toward emotional stimuli and is widely used in studies of anxiety, depression, and emotional regulation.

Task Flow

Step

Description

Instruction

A textbox (instruction_text) presents task instructions in Chinese. Participant presses the space bar to start.

Fixation

A fixation cross “+” is shown at the center of the screen.

Cue Pair

A pair of face images (left and right) are displayed briefly.

Interval

A short blank screen or fixation is shown after the faces.

Target

A dot appears either on the left or right side; participant responds via arrow keys.

Block Break

After each block, performance feedback is presented and participants rest.

Goodbye

A final thank-you screen ends the session.

Configuration Summary

All key settings are stored in the config/config.yaml file.

Subject Info (subinfo_fields)

Participants are registered with:

  • Subject ID (3-digit number from 101–999)

  • Session Name

  • Experimenter Name

  • Gender (Male or Female)

Localized prompts are available via subinfo_mapping.

Window Settings (window)

  • Resolution: 1920 × 1080

  • Units: deg

  • Fullscreen: True

  • Monitor: testMonitor

  • Background color: black

Stimuli (stimuli)

Stimulus Name

Type

Description

fixation

text

Central fixation cross “+”

left_stim, right_stim

image

Face stimuli dynamically assigned per trial

left_target, right_target

circle

Target dots shown left or right

block_break

text

Mid-task break message

instruction_text

textbox

Task instructions in Chinese

good_bye

textbox

End-of-task thank-you screen

Stimulus images are dynamically assigned based on trial conditions using an asset_pool.

Timing (timing)

Phase

Duration

Fixation

0.3 seconds

Face Cue

0.5 seconds

Interval

0.4–0.6 seconds (randomized)

Target Response Time

1.2 seconds

Conditions (task.conditions)

Each condition represents the combination of:

  • Emotion pair (Positive-Neutral, Negative-Neutral, Neutral-Neutral)

  • Gender of faces (Female, Male)

  • Target side (Left, Right)

Example condition codes:

  • PN_F_L – Positive (left) / Neutral (right), Female faces, Target Left

  • SN_M_R – Negative (left) / Neutral (right), Male faces, Target Right

  • etc.

There are 18 conditions in total.

Triggers (triggers)

Each condition has a full set of triggers:

Event

Trigger Code Example (for PN_F_L)

Fixation Onset

11

Cue Onset

12

Target Onset

13

Key Press

14

No Response

15

General experiment and block onset/end triggers:

  • Experiment Start: 98

  • Experiment End: 99

  • Block Start: 198

  • Block End: 199

Running the Task

python main.py